Electric valve circuit



ELECTRIC VALVE C IRCUIT Filed July 1, 1956 2 Sheets-Sheet 1 (O iii Figi.

Inventor: Richard G. Lorraine,

by H is Attorney.

Dec. 21, 1937. R. e. LORRAINE ELECTRIC VALVE CIRCUIT Filed July 1, 1956 2 Sheets-Sheet 2 IYWVQTTCOT: Richard G. Lorraine Attorn ey.

Patented Dec. 21, 1937 UNITED STATES PATENT ()FFltZE ELECTRIC VALVE CIRCUIT New York Application July 1,

Claims.

My invention relates to electric valve translating apparatus and more particularly to control or excitation circuits for electric valve means of the type employing ionizable mediums.

Heretoiore in electric valve translating systems there have been devised numerous arrangements for controlling the operation of the electric valve circuits in accordance with normal and abnormal operating conditions. Many of the prior art arrangements have provided control circuits for modifying the operation of the system to effect a complete interruption of service when the system departs from a predetermined plan of operation. Other of the prior art arrangements have been concerned with control arrangements for modifying the voltage, current or power factor conditions in accordance with abnormal conditions of associated circuits. With the increased application of electric valve translating apparatus in the power field where the electric valve apparatus has been constructed to withstand certain irregular operating conditions of moderate severity, there is a decided need for control apparatus to modify temporarily the plan of operation of the electric 25 valve translating systems to correct a transient abnormal condition Without necessitating an in terruption of service. For example, where a plurality of electric valves are connected in an electric translating system and are arranged to be rendered conductive in a predetermined order or sequence, it is sometimes desirable to modify the plan of sequential energization of the electric valves to correct an abnormal operating condition of one of the electric valves without interfer- 33 ing with the operation of the other electric valves in the system.

An object of my invention is to provide a new and improved electric valve translating circuit.

Another object of my invention is to provide 40 new and improved control or excitation circuits for electric valve translating apparatus.

A further object of my invention is to provide new control or excitation circuits for electric valve translating systems which correct abnormal operating conditions of the systems without sacrificing continuity of service.

In accordance with the illustrated embodiments of my invention, I provide control or excitation circuits for electric valve means particularly of 50 the type employing ionizable mediums such as gases or vapors. The electric valve translating apparatus may comprise a plurality of are discharge paths each employing a control member of the immersion-ignitor type which renders the as- 55 scciated arc discharge path conductive. In order Ill) 1936, Serial No. 88,391

to increase the current rating of electric valves of this type, many of these valves have been provided with cooling coils or conduits which are placed in the vicinity of the arc discharge paths and by the use of suitable cooling fluids are effective to maintain the temperature of the electric valves below predetermined maximum values. By virtue of this constructional arrangement of the electric valves of this type, since the vapors condense on the coling coils, the cooling coils and the condensed vapors under some operating conditions act as cathodes,which condition effects a rapid deterioration disintegration of the cooling coils and deleteriously affects the to of the electric valves. To obviate this difficulty, I provide an excitation circuit for controlling electric valves of this type in which an associated conrol electric valve is rendered conductive to energize the immersion-ignitor control member as soon as the main electric valve conducts current.

For example, in electric valve translating circuits where a plurality of electric valves are rendered conductive in a predetermined order by selective energization of the various control members I provide apparatus associated with the anode-cathode circuits of the individual arc discharge paths for modifying the operation of the associated excitation circuits to advance the time of energize.- tion of particular immersion-ignitor control members relative to the next succeeding normal interval of conduction when the arc discharge paths conduct current at any time other than during the predetermined intervals. This selective energization of the immersion-ignitor control members of the electric valves is a complished by mploying a plurality of sources of alternating potential to render conductive auxiliary or control electric valves, each of which is associated with a diiierent one of the various excitation circuits. In one modification of my invention diagrammatically shown, inductive devices such as auto-transformers are connected in the anodecathode circuits of the main or power electric valves to control the potentials impressed on the anodes of the control electric valves in accordance with an electrical condition such as the current of the main electric valves to efiect the desired advance in the time of energization of the immersion-ignitor control members. In another modification of my invention, I employ auto-transformers connected the anode-cathode circuits of the electric valves to modify the potentials impressed on the control members of the control electric valves to advance the time of energization of the immersion-ignitor control members in l the event the main electricvalves conduct current at any time other than during predetermined intervals.

For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

Fig. 1 of the accompanying drawings diagrammatically shows an embodiment of my invention as applied to polyphase electric valve translating systems in which the excitation circuits for the main electric valves are controlled or modified in operation to advance the time of energization of the control member of the associated main electric valve in the event the main electric valve conducts current at any time other than during the predetermined normal intervals of conduction. Figs. 2 and 3 show arrangements for controlling electric valves in a polyphase electric valve translating system and in which the control electric valves in the excitation circuits are modified in operation by controlling the potentials-impressed on the control members of the control electric valves.

Referring now to Fig. l of the accompanying drawings, my invention is diagrammatically shown as applied to an electricvalve translating system for transmitting energy between a polyphase alternating current circuit and a direct current circuit. A three phase alternating current circuit I is connected to a direct current circuit 2 through electric translating apparatus including a transformer 3 for transforming three phase alternating current to quarter phase alternating current. Electric valves 4, 5, 6 and l are associated with the secondary windings of transformer 3 and are preferably of the type employing an ionizable medium such as a vapor. Each of the electric valves 4, 5, 6 and 1 provides an arc discharge path and includes an anode 8, a mercury pool cathode 9 and an associated immersion-ignitor control member i ii. For the purpose of explaining my invention, I have chosen to represent electric valves 4, 5, 6 and l as being of the type employing a cooling coil Ii located in the vicinity of the arc discharge path and which are associated with the cathodes 9. These cooling coils, through which any suitable cooling fluid may be passed, are used to maintain the temperature of the electric valves below predetermined maximum temperatures to increase the current rating of the electric valves.

In order to control the conductivity of electric valves 4, 5, 5 and T and to render these valves conductive in a predetermined order or sequence, I provide excitation circuits 12,13, 54 and 15. Each of these excitation circuits includes an electric valve l6, preferably of the type employing an ionizable medium such as a gas or a vapor, and having an anode H, a cathode l8 and a control member l9. In Fig. 1 the electric valves 16 have been shown as being of the type employing a screen grid 20 which is connected to the, cathode l8. The excitation circuits l2, l3,

ill and i5 are energized in accordance with an electrical condition, such as the voltage appearing across the electrodes 8 and 9 of the associated electric valve. Inductive means, such as autotransformers 2i, 22, 23and 24, are employed to impress on the anodes ll of control electric valves 25 potentials which vary in accordance with an electrical condition such as the current conducted by the main electric valves 4, 5, 6 and i. Current limiting resistances 25, 26, 2'! and 28 are connected in series relation with the autotransformers 2|, 22, 23 and 24 and the control electric valves it of excitation circuits l2, l3, I4 and I5, respectively. Inductances or smoothin reactors 29, 3|), 3| and 32 are connected in series with the various secondary windings of transformer 3 and the auto-transformers 2|, 22, 23, and 24, respectively.

A plurality of sources of alternating potential are supplied through conductors 33 to render the control electric valves conductive in a predetermined order, thereby effecting sequential energizaticn of the associated immersion-ignitor control members iii of electric valves 4, 5, B and 7. Any suitable phase shifting arrangement, such as the rotary phase shifting device 34, may be employed to supply quarter-phase alternating potential from the three phase alternating current supply circuit I. Current limiting resistances st, 36, 37 and 38 are connected in serieswith the control members 19 of control electric valves it.

The general principles of operation of the embodiment of my invention diagrammatically shown in 1 may be best explained by considering the operation of the electric valve translating system when energy is being transmitted from the three phase alternating current circuit I to the direct current circuit 2. As will be well understood by those skilled in the art, the main or power electric valves 4, 5, 6 and I will be rendered conductive in a predetermined order or sequence to supply unidirectional current to the direct current circuit 2. The electric valves 4, ii, 5 and l are rendered conductive by the proper sequential energization of the associated immersion-ignitor control members l0. During normal operation this sequential energization of the control members I0 is accomplished by means of the control electric valves l6 in the excitation circuits l2, l3, I4 and I5 which are rendered conductive by means of the periodic alternating potentials supplied through conductors 33 and which are impressed on the control members 19 of the control electric valves I 6. For example, at the instant immediately preceding the time at which electric valve 4 is rendered conductive, the potential appearing between the anode 8 and the cathode 9 of electric valve 4 will be relatively great and of. a polarity tending to establish an arc discharge in the associated arc discharge path. If electric valve I6 is rendered conductive at this instant, the associated immersion-ignitor control member ID will be energized by the current which flows incident to the completed electric circuit established between the auto-transformer 2i and the cathode 5 of electric valve 4. By the proper design of this circuit, the current which flows during this short interval will be suificient to render the electric valve 4 conductive. Immediately after the electric valve 4 is-rendered conductive, the voltage appearing between the anode 8 and the cathode 9 will be reduced to a relatively small value and the current supplied to the immersion-ignitor control member will be reduced proportionately. It is, therefore, to be noted that the electric valves a, 5, 6 and l are rendered conductive in a predetermined sequence.

In electric valve translating circuits under some conditions of operation, the electric valves depart from'the normal sequential operation by conducting current during intervals not in agreement with the sequential plan of energization. In many applications this irregularity of operation is not objectionable in so far as the operating conditions of the associated electric circuits are concerned. However, this irregular operation may be cccasioned by abnormal operation of the particular electric valve or are discharge path and it may be desirable to render the electric valve conductive in the ordinary or proper way to correct this condition. For example, referring to the type of electric valve shown in Fig. 1 of the drawings, the condensed mercury vapor on the cooling coils ll under some conditions of operation acts as a cathode and by virtue of the geometry of the electric valve may cooperate with the anodes 8 to establish arc discharges in the electric valves at times other than during the normal periods of conduction. This phenomenon eventually results in deterioration and disintegration of the cooling coil H and deleteriously afiects the life of the electric valve. In order to correct this irregular operation,Ihavefoundthat it is desirable to render the electric valves conductive immediately in the proper manner, that is by energizing the immersion-ignitor control members I!) as soon as the electric valve conducts current.

If it be assumed that for any reason the electric valve 4, for example, conducts current at a time not in agreement with the normal plan of energization, the current flowing through the autotransformer 2! will induce in the winding of auto transformer 2| a voltage to render the control electric valve l6 conductive and which effects energization of the associated immersion-ignitor control member It] by advancing the time of energization of the control member relative to the next succeeding normal interval of conduction to establish a cathode spot on the mercury pool cathode 9, thereby rendering the electric valve 4 conductive in the proper manner. If the above considered irregular operation has been occasioned by the establishment of a cathode spot on the cooling coil I l, the arc discharge will be transferred from the cooling coil i l to the cathode 9. The excitation circuits l2, l3, l4 and I5 may be designed so that the potential appearing across the auto-transformers 2|, 22, 23 and 24 when impressed on the anodes ll of electric valves I6 renders the electric valves l6 conductive even though the periodic potential impressed on the control members l9 may be negative relative to the cathode !8.

In Fig. 2 of the accompanying drawings another embodiment of my invention is diagrammatically shown as applied to an electric valve translating system for transmitting energy between a three phase alternating current circuit 39 and a direct current circuit 40 through a transformer 41 and electric valves 42, 43, 44 of the type employing an ionizable medium, such as a vapor, and each having an anode 45, a mercury pool cathode 46 and an immersiondgnitor control member 41. Excitation circuits 48, 49 and 50 are associated with the control members 47 of electric valves 42, 43 and 44, respectively, and are employed to render the electric valves conductive in a predetermined order. Each of the excitation circuits 48, 49 and 55 is energized in accordance with the voltage appearing across the anode and the cathode 45 of the associated electric valve. Each of the excitation circuits 48, 49 and 50 includes a control electric valve 5!, preferably of the type employing an ionizable medium such as a gas or vapor, and each has an anode 52, a cathode 53 and a control member 54. Resistances 55 are connected between the cathodes 53 of the electric valves 5| and the cathodes 48 of the associated electric valves so that the excition current flows through the immersion-ignitor control members 41. In order to render the electric valves 5! and excitation circuits 48, 49 and 50 conductive in a predetermined sequence, a plurality of sources of alternating potential are obtained from the alternating current circuit 39 through any conventional phase shifting device, such as a rotary phase shifter 55, and transformer 57 having primary windings 58 and secondary windings 59.

To render the electric valves 5| conductive in the event the associated main or power electric valves conduct current at any time other than during the normal periods of conduction, I employ transformers iii], and 62 which are associated with electric valves 42, 43 and 44, respectively. Each of the transformers Bil, 6i and 62 includes a winding 53 and a winding 64 inductively associated with each other. One terminal of the winding 63 is connected to the anode 45 of electric valve 42 and the other terminal is connected to the anode 52 of electric valve 55. The right-hand terminal of winding 54 of transformer 50 is connected to the control member 54 of electric valve 5i and the left-hand terminal of winding 54 is connected to one of the secondary windings 58 of transformer El through a current limiting resistor 65. A negative biasing potential is impressed on the control members 54 of control electric valves 5| by means of any suitable biasing the battery 66.

The operation of the embodiment of. my invention diagrammatically shown in Fig. 2 is substantialy the same as that described above in connection with the embodiment diagrammatically shown in Fig. 1, differing only in the manner in which the control electric valves 5i are rendered conductive in the event the associated main or power electric valve conducts current during intervals other than during the normal periods of conduction. During normal operation, the control electric valves 5! in excitation circuits 48, 49 and 55 will render electric valves 42, 43 and 44 conductive in predetermined order to supply direct current to the direct current circuit 40. Howover, if one of the power electric valves, for example electric valve 42, departs from this sequential plan of operation, current flowing through winding of transformer 59 will induce a voltage in winding 84 which will render the control electric valve 55 conductive to effect energization of the immersion-ignitor control member 41 of electric valve 42. In this way, by advancing the time of energization, each of the electric valves 42, 43 and 42- will be rendered conductive in the proper or predetermined manner even though the electric valves depart from the sequential plan of energization.

Fig. 3 diagrammatically shows an electric valve circuit for transmitting energy between an alternating current circuit and a direct current circuit. This arrangement is somewhat similar to the arrangement or Fig. 2 and corresponding elements have been assigned like reference numerals. Excitation circuits 51, 88 and 69 are associated with electric valves 42, 43 and 44, respectively, and serve to render these valves conductive in a predetermined sequence. Each of the excitation circuits El, 58 and 69 includes a control electric valve 70 having an anode H, a cathode 72 and a control member 73. To impress on the immersion-ignitor control members 47 potentials of suitable wave form and to furnish impulses of current to render the valves conductive, I employ circuits ":4, l5 and '16 of the means such as impulse type which are associated with excitation circuits 6?, 75B and 89, respectively, and

which are alike in construction and arrangement. The circuits i i, 15 and E are energized from the alternating current circuit 35 through any conventional phase shifting arrangement such as the rotary phase shifter ll and through a transformer 78 having primary windings 19 and secondary windings 8t, 8! and 32.

Each of the secondary windings 85, Si and 82 is provided with an electrically intermediate con nection 83. Considering circuit i l, in particular, a capacitance 84 is connected between the intermediate connection 83 and the upper terminal of winding ti in series relation with a unidirectional conducting device 85 and a resistance 86 and is charged through the device 85 and re-' sistance during positive half cycles of potential. A phase shifting arrangement including a capacitance 81 and a resistance 88 is connected between the lower terminal of winding 39 and the intermediate connection 83.

To render control electric valves conductive and hence to advance the time of energization of the immers'ion-ignitor control members t! of electric valves s2, 33 and i i in the event these valves depart from the normal sequential plan of operation, transformers'dii, 9i? and iii each having a primary winding 92 and a secondary winding 93, are connected in series relation with the anode-cathode circuits of these valves. The upper terminals of secondary windings 533 are connected to the common juncture of the capacitance 8i and the resistance 38 through a current limiting resistance 9 The lower terminals of windings 93 are connected to the control members 13 of electric valves it through a resistance 95.

The operation of the electric valve system diagrammatically shown in Fig. 8 is substantially the same -as that described in connection with Fig. 2 with the exception that the excitation circuits 67, 68 and 69 are of the type arranged to supply impulses of the current to the immersion-ignitor control members of eiectric valves 32, 43 and 43 to render these valves conductive in a predetermined order or sequence to supply direct current to the direct current circuit 48. For the purpose of explaining my invention, the operation of excitation circuit 5'! will be considered in particular. During half cycles of potential when the upper terminal oi'secondary winding 8b of transformer i8 is positive relative to the intermediate connection the upper plate of capacitance will be charged positively. By virtue of the unidirectional conducting characteristics of device 85, this charge will be maintained. During normal operation, the

control electric valve ill will be rendered conductive during predetermined recurrring intervals by means of the periodic potential impressed on the control member 13 by means of the phase shifting arrangement including capacitance 8'1 and resistance 86. This periodic potential is impresssed on the control member l3 through 'a resistance 95, secondary winding 93 of transformer 89 and resistance 95. When the periodic potential impresssed on a control member '53 of 7 when the electric valve 42, for example, conducts current at a time not in accordance with predetermined periods of conduction, the cur-' rent which flows through the primary 'winding 92 of transformer 89 will induce a voltage in the secondary winding 93 of this transformer to modify the potential impressed on the control member 13 of control electric valve H! so that the electric valve 18 is rendered conductive to ad-v Vance the time of energization of the control member 47 of electric valve G2.

Although in the embodiments of my invention diagrammatically illustrated in Figs. 1, 2 and 3 I have explained the operation of the electric valve translating systems as arrangements for transmittting energy from alternating cur rent circuits to direct current circuits, it is to be noted that my invention in its broader aspects may be applied to electric valve translating systems generally for transmitting energy in either direction, between alternating current circuits and direct current circuits, or between alternating current circuits of the same or different frequencies. Furthermore, even though my invention has been shown as applied to electric valves of the type employing immersion-ignitor control members, it is to be understood that my invention may be applied to other types of 'elec-. tric valves employing ionizable mediums and that it may be applied to electric valves of the high vacuum type.

While I have shown and described my invention as applied to a particular system of connections and as embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modifications may be made without departing from my invention, and I, therefore, aim in the appended claimsto cover all such changes and modifications as fall within the'true spirit and scope of my invention. a

What I claim as new and desire by secure by Letters Patent of the United States is:

1. In combination, an electric valve having an anode, a cathode and a control member, an excitation circuit energized in accordance with the voltage appearing across the anode and the cathode of said electric valve means comprising a control electric valve for energizing said control member to render said electric valve means conductive during normal predetermined intervals of conduction, and means responsive to the current in the anode-cathode circuit of said firstmentioned electric valve means for controlling said second-mentioned electric valve means to advance'the time of energization of said control member relative to the next succeeding normal interval of conduction in the event said firstmentioned electric valve means conducts current at any time other than, during said predetermined intervals.

2. In combination, an electric valve means having a control member, an excitation circuit for energizing said control member to render said electric valve means conductive during normal predetermined intervals of conduction compris ing a control electric valve having an anode and a cathode, and means responsive to an electrical condition of said first-mentioned electric valve means for controlling the potential impressed on said anode of said second-mentioned electric valve means to render said second-mentioned electric valve means conductive and to effect an advancement in the time of energization of said control member relative to the next succeeding normal interval of conduction of said first-mentioned electric valve means in the event said first-mentioned electric valve means conducts current at any time other than during said predetermined intervals.

3. In combination, an alternating current circuit, a direct current circuit, electric translating apparatus interconnecting said circuits comprising a plurality of arc discharge paths each having a control member, a plurality of excitation cir cuits each associated with a different one of said arc discharge paths and for energizing the associated one of said control members to render each of said are discharge paths conductive during predetermined intervals of conduction and each comprising an electric valve means connected to energize said associated one of said control members in accordance with the voltage appearing across said associated arc discharge path, and individual means responsive to the current in said are discharge paths for advancing the time of energization of said associated control members relative to the next succeeding interval of conduction for the associated arc discharge paths in the event said arc discharge paths conduct current at any time other than during said predetermined intervals.

4. In combination, an electric valve means having an arc discharge path and a control member of the immersion-ignitor type, an excitation circuit for energizing said control member comprising a source of periodic potential, a capacitance connected to be energized from said source and an electric valve connected to periodically discharge said capacitance to effect energization of said control member to render said are discharge path conductive during predetermined intervals, and means for controlling said second mentioned electric valve to advance the time of energization of said control member relative to the next succeeding interval of conduction in the event said first mentioned electric valve means conducts current at any time other than during said predetermined intervals.

5.111 combination, an electric valve means comprising arc discharge path and having an anode, a cathode and a control member, a. cooling member in the vicinity of said arc discharge paths, an excitation circuit for energizing said control member to render said electric valve means conductive during predetermined intervals, and means for effecting energization of said control member in the event an electric discharge is established between said cooling member and. said anode.

RICHARD G. LORRAINE. 

